I like to remove the female from the large tank and move her to a small container so that she can't see any other fish for several days to a week and mass feed mosquito larva-I will let her see the male (that I have in a small container too) at least once a day so that I can monitor their behavior. Once both are showing interest/flirting a bit I place them in the spawning tank.

All of my females are kept in a sorority tank until I choose one for breeding.
I once had a female HM breed with a male PK (mistaken identity) in my sorority tank so I don't believe using sorority females should be a problem.

Are your females in a sorority or each in individual tanks? All my female HM's beat the males...and the males are bigger..seems that when i separate each female into tanks of their own they get more aggressive..and the males having huge tails..fall victim to the female aggression..now to fix this i have recruited more plakat males and so far its working..the plakat boys are beating the girls into submission..because of their short temper and quick moves ( short fins enables more agility) unlike the regular HM's who cant move as fast because of their long fins..

yes good move...she needs to focus on him alone...so what i usually do is the chimney set up where i have her in a jar..approximately 1.5-2 liter and place it into the males tank..for like a day so they can battle it out without biting each other...and from then you can oberserve signs..and place them together when he builds a nest and stays under it or if she gets her stripes and is poised on following the male..you will know what signs you're looking for :)..